Implemented DropColumn for sqlite

Database/sqlalter.py

@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import os
+import time
 
 import sqlalchemy as sqla
 from sqlalchemy.ext.compiler import compiles
@@ -55,8 +56,42 @@ def visit_drop_column(element, ddlcompiler, **kw):
     return 'ALTER TABLE %s DROP COLUMN %s'%(tname, colname)
 
 @compiles(DropColumn)
+##
+# @warning Returns more than one query @ref Database.sqlutils.ddl_execute
 def visit_drop_column(element, ddlcompiler, **kw):
-    raise NotImplementedError('Drop column not yet implemented for '+str(ddlcompiler.dialect.name))
+    prep = ddlcompiler.sql_compiler.preparer
+    tname = prep.format_table(element.table)
+
+    #Temporary table
+    tmpname = str(element.table)+'_copydropcol'
+    tmpTable = sqla.Table(tmpname, sqla.MetaData())
+    tmptname = prep.format_table(tmpTable)
+
+    query =  'ALTER TABLE %s RENAME TO %s; '%(tname, tmptname)
+
+    colname = prep.format_column(element.col)
+
+    meta = sqla.MetaData()
+    newtable = sqla.Table(element.table, meta)
+    clist = element.table.columns
+
+    cols = []
+    for col in clist:
+        if col.name != element.col.name:
+            newtable.append_column(col.copy())
+            cols.append(prep.format_column(col))
+    cols=', '.join(cols)
+
+    query += str(sqla.schema.CreateTable(newtable).compile(dialect = ddlcompiler.dialect))+';'
+
+    query += 'INSERT INTO %s ( %s ) SELECT %s FROM %s;' % (newtable, cols, cols, tmptname)
+
+    query += 'DROP TABLE %s'% (tmpname)
+
+    return query
+
+
+    #raise NotImplementedError('Drop column not yet implemented for '+str(ddlcompiler.dialect.name))
 
 class AlterColumn(sqla.schema.DDLElement):
     """ Defines the DDL for changing the type of a column """

Database/sqlutils.py

@@ -91,11 +91,20 @@ def getTable(cls):
     engine = cls.getDbE()
     return sqla.Table(cls.table, meta(engine))
 
+## This function is intended to execute ddl defined in sqlalter
+# @warning There is a dirty workaround here, DDL should returns only one query, but DropColumn for sqlite has to return 4 queries (rename, create, insert, drop). There is a split on the compiled SQL to extract and execute one query at a time
+# @param ddl DDLElement: Can be an Database.sqlalter.DropColumn Database.sqlalter.AddColumn or Database.sqlalter.AlterColumn
+# @param db_engine: A database engine
+# @return True if success, else False
 def ddl_execute(ddl, db_engine):
     conn = db_engine.connect()
     req = str(ddl.compile(dialect=db_engine.dialect))
-    logger.debug("Executing custom raw SQL query : '"+req+"'")
-    ret = conn.execute(req)
+    queries = req.split(';')
+    for query in queries:
+        logger.debug("Executing custom raw SQL query : '"+query+"'")
+        ret = conn.execute(query)
+        if not bool(ret):
+            return False
     conn.close()
-    return bool(ret)
+    return True
 

EditorialModel/fields.py

@@ -85,7 +85,8 @@ class EmField(EmComponent):
     # @return bool : True if deleted False if deletion aborded
     # @todo Check if unconditionnal deletion is correct
     def delete(self):
-        class_table = self.get_class_table()
+        dbe = self.__class__.getDbE()
+        class_table = sql.Table(self.get_class_table(), sqlutils.meta(dbe))
         field_col = sql.Column(self.name)
         ddl = DropColumn(class_table, field_col)
         sqlutils.ddl_execute(ddl, self.__class__.getDbE())

EditorialModel/test/test_field.py

@@ -129,7 +129,6 @@ class TestField(FieldTestCase):
         self.assertIn(field_column.name, field_table_columns)
         pass
     
-    @unittest.skip("Delete not implemente for sqlite...")
     def test_deletion(self):
         field_names = ['field1', 'field2']
         for name in field_names:
@@ -143,7 +142,7 @@ class TestField(FieldTestCase):
             for deleted_name in field_names[:i+1]:
                 self.assertNotIn(deleted_name, cols, "Column is  not deleted")
             for not_deleted_name in field_names[i+1:]:
-                self.assertIn(deleted_name, cols, "A bad column was deleted")
+                self.assertIn(not_deleted_name, cols, "A bad column was deleted")
                 
             with self.assertRaises(EmComponentNotExistError, msg="This field should be deleted"):
                 EmField(name)